Recyclerview无法平滑滚动并卡在前10个项目上

Question

我尝试使RecyclerView平滑滚动。我只加载10个项目，加载时带有ProgressBar，加载后消失。但是我的RecyclerView停留在第一个元素上。

我用过：

recyclerView.setNestedScrollingEnabled(false);

没有成功。

class SummeryRecyclerViewAdapter(
    var context: Context, val resultList: ArrayList<Result>
) : RecyclerView.Adapter<SummeryRecyclerViewAdapter.ViewHolder>() {

    lateinit var onloadMoreListener: OnLoadMoreListener

    override fun onCreateViewHolder(parent: ViewGroup?, viewType: Int): SummeryRecyclerViewAdapter.ViewHolder {
        return ViewHolder(LayoutInflater.from(parent?.context).inflate(R.layout.sigle_row_for_summery, parent, false))
    }

    override fun onBindViewHolder(holder: ViewHolder?, position: Int) {
    // MY CODE IS HERE (ITS LONG LIME CODE)}
    }

    override fun getItemId(position: Int): Long {
        return position.toLong()
    }

    override fun getItemViewType(position: Int): Int {
        return position
    }

    override fun getItemCount(): Int {
        return resultList.size
    }

    class ViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
        // MY VIEW ITEMS HERE ...
    }

    fun setLoadMoreListener(onLoadMoreListener: OnLoadMoreListener) {
        this.onloadMoreListener = onLoadMoreListener
    }

    interface OnLoadMoreListener {
        fun onLoadMore()
    }

    fun addMoreData(articleLists: MutableList<Result>) {
        resultList.addAll(articleLists)
        notifyItemRangeInserted(resultList.size + 1, articleLists.size)
    }
}

我的活动代码：

class SummeryActivity : AppCompatActivity(), SummeryRecyclerViewAdapter.OnLoadMoreListener {

    private lateinit var summeryRecyclerViewAdapter: SummeryRecyclerViewAdapter
    var last_no: Int = 0
    var isLoading: Boolean = false
    var countLoad: Int = 1
    val resultHandler = ResultHandler(this)
    var exam_id: Int = 0

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_summery)
        window.statusBarColor = resources.getColor(R.color.colorPrimaryDark)
        summery_btnCloseActivity.setOnClickListener { finish() }

        exam_id = intent.getIntExtra("examId", 0)
        val myData = resultHandler.getResultData(exam_id)
        Log.e("myData", "${myData}")
        summeryRecyclerView.layoutManager = LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false)

        summeryRecyclerViewAdapter = SummeryRecyclerViewAdapter(this, getItems())
        summeryRecyclerView.setNestedScrollingEnabled(false);
        summeryRecyclerView.adapter = summeryRecyclerViewAdapter

        summeryRecyclerViewAdapter.setLoadMoreListener(this)

    }

    fun getItems(): ArrayList<Result> {
        val userList: ArrayList<Result>
        userList = resultHandler.getResultData(exam_id, "10", last_no)
        last_no = userList.size
        return userList
    }

    override fun onLoadMore() {
        if (resultHandler.getResultData(exam_id).size != last_no) {
            if (!isLoading) {
                isLoading = true
                Handler().postDelayed({
                    load_progress_summery.visibility = View.VISIBLE
                    summeryRecyclerView.smoothScrollToPosition(summeryRecyclerViewAdapter.itemCount)
                }, 100)
            }
            Handler().postDelayed({
                isLoading = false
                load_progress_summery.visibility = View.GONE
                val userList: ArrayList<Result>
                userList = resultHandler.getResultData(exam_id, "10", last_no)
                last_no += userList.size
                countLoad += 1

                summeryRecyclerViewAdapter.addMoreData(userList)
            }, 10 * 100)
        } else {
            load_progress_summery.visibility = View.GONE
        }

    }
}